Re: The affects of Waste Vegetable oil on TDI\'s
Drivbiwire: First off, thanks for contributing for this thread. You've got a lot of experience dealing with these engines, far more than I do, and I respect your opinion.
However, what better place to be disagreeable than the internet?
I'd like to refer you back to the second paragraph of my original post:
Unfortunately, it's hard to prove or disprove vegetable oil as a direct cause of IP failure, since few TDIs have been run on VO for their entire lifetimes, and it's not like failure of pumps running exclusively on diesel is unheard of.
You said:
I can't count the number of injection pumps replaced due to WVO/SVO use. Injection pumps that I have seen failed due to excessive wear on the pump cam plate rollers, glycerine build on the electronic sensors (Fuel temp sensors), clogged timing advance selenoid preventing timing control, Damaged injectors (Internal and nozzle hole wear), failed low stage pump (Vane pump) just to name a few.
I'm sure you've seen these problems in cars converted for SVO. Now, I'm not trying to be a jerk here, but are you saying you've
never seen any of these problems on pumps running only D2? The usual candidate for a SVO/WVO conversion is a car that is beyond warranty coverage, typically 100K+ miles -- people are reluctant to mess with it before then. Who knows what fuel those pumps have seen and what conditions they've been operating under before they see a drop of VO. Can you say definitively that the failure of those pumps were due to the use of properly heated, clean, dry vegoil? Did you tear them down and document the wear prior to conversion (in retrospect, I wish I had done so), then monitor or ensure fuel quality after conversion? If you did, I'd love to see the results. If not, all you've got is the same thing people with engines running successfully on VO have: anecdotes.
I'm sure it's possible to have a pump/injectors fail on VO. It's also possible to have them fail on diesel. Anecdotes are great, but we need one of two things to determine something with certainty: data that demonstrates causation, or data that show relative probabilities. Otherwise your data is uncontrolled (and yes, I'm a scientist.)
The point of my original post is that so far I haven't seen either form of data yet. I'm not arguing that SVO/WVO is perfectly safe, like some VO users/advocates; as far as I'm concerned, the question is still open.
On average most WVO/SVO owners that I replace pumps for make it about 1 year or so before destroying the injection pump.
It's been 11 months. Like I said, if that happens I'll let you know.